The proposal is to further test, refine, and exploit a procedure developed in this laboratory which uses 2-deoxyglucose (2DG) to measure short-term changes in glucose metabolic rates in different parts of the brain. The well known 2DG method of Sokoloff measures glucose metabolic rate radioautographically by the accumulation of 14C-2DG-6-phosphate (DG6P) during a 45 min time period. This long period is required largely to dissipate the 2DG, which would be indistinguishable in the radioautograph from its phosphate metabolite. Because many events of interest in brain occur within a much shorter time frame, the 45 min delay represents a distinct limitation on the original 2DG method. The new method uses non-radioactive 2DG and substitutes for radioautography, the direct enzymatic measurement of DG6P, 2DG, and glucose in the brain areas of interest. Times as short as one minute are practical and analyses of brain areas as small as large perikarya are feasible. Physical separations of the three compounds are not required. The assays are based on enzymatic methods which distinguish DG6P from G6P, and which are capable of virtually unlimited amplification, according to need.